1. Field of the Invention
The present invention relates to an arrangement structure of heat exchangers in a condensing gas boiler, and more particularly, to an arrangement structure of heat exchangers in a condensing gas boiler which maximizes a heat transfer area and makes present heat and condensing conditions, to thereby improve a heat exchanging efficiency, and to then accomplish compactness and corrosion resistance of the boiler.
2. Description of the Related Art
A boiler for use in general homes and buildings is used for heating water and supplying hot water, which is divided into a fuel oil boiler and a fuel gas boiler, according to a type of a fuel used.
When a fuel oil boiler and a fuel gas boiler each having an identical capacity are compared with each other, the former is cheaper than the latter in view of its purchasing price, but the latter is more economic than the former in view of an amount of fuel consumed.
However, consumer's expenses are almost same on a long-term basis in both cases of a fuel oil boiler and a fuel gas boiler. Thus, fuel gas boilers are used in places where city gas is supplied, but fuel oil boilers are used in other places where city gas is not supplied.
Meanwhile, vapor generated in the course of burning gas contacts low-temperature matter or air to then be changed into water (H2O). In this case, heat energy is created. A gas boiler, which is designed to re-absorb the generated heat in order to heighten a thermal efficiency, is called a condensing gas boiler. Such a condensing gas boiler has a thermal efficiency higher than that of an ordinary gas boiler and also can save a fuel cost remarkably. Accordingly, the condensing gas boilers are being widely used.
The condensing gas boiler uses combustion heat and directly heats circulation water, and re-absorbs condensed latent heat in exhaust gas, to thus heighten a thermal efficiency. Considering the thermal efficiency, the condensing gas boiler is made of a material of copper. However, an internal heat exchanger is corroded due to acid moisture generated at the time of a condensation process, and sulfuric oxide, nitric oxide, and combustion heat included in exhaust gas. To suppress it, aluminum or stainless steel having a corrosion-resistant property is used for the heat exchanger.
Although aluminum or stainless steel has a good corrosion-resistant property, its thermal efficiency is low. Thus, the heat exchanger should be designed largely in order to assume an identical calorie. As a result, the condensing gas boiler cannot be compact.
Also, the conventional condensing gas boiler is designed so that an area of a heat exchanger for a present heat portion differs from that of a heat exchanger for a latent heat portion, in order to identify a flowing direction of exhaust gas. As a result, a heat exchanging efficiency is reduced.